Safety mechanism for hoisting apparatus



oct. zo, 1925.

E. J. FWERS SAFETY MECHANSM FOR HOISTING `APPARATUS Flec April 20, 19252 Shania-Sham l E. J. POWERS SAFETY MECHANISM FOR HOZSTING APPARATUS yFiled April 20, 1925 2 Sheets-Sheet 2 Imemort' aiu/afd] *pau/'6215,

Patented Oct. 20, 1925.

UNITED STATES EDWARD J- BOWERS 0F OAK ARK, ILLINOIS.

sArrrx MECHANISM FOR HOISTING APPARATUS- Applcaton filed April 20, 1925.Serial NQ. 24,382.

To all' whom t may. concern.'

Be it known that I, EDWARD J. BOWERS, a citizen of the United States of-America, residing at Oak Park, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements 1n SafetyMechanism for Hoisting Apparatus, of which the following is a,specification.

This invention relates to automatic catch mechanisms and the like,whereby thel rotationA of the primary pinion of the gearing of themechanism, other than,V by the driving shaft, is prevented, when fromany accidental cause said driving shaft fails to function as a driver,and the present improvement has for its objects* To provide a structuralformation and association of parts in which the primary pinion or likemember of the `gearing of a hoisting or like mechanism, is caught andheld from rotation in either direction, when from any accidental causethe driving or power shaft-carrying said pinion fails to function. Theconstruction involving a relative formation of parts wherein the drivingor power shaft has a limited independent turning movement `in relationto the aforesaid pinion, with said pinion carrying a pair of reverselyarrzuiged` ratchet pawls or dogs for alternating engagement with acircular ratchet formation on a portion of the stationary supportingframe of the apparatus, to catch and hold said pinion against rotationexcept when the said pinion is positively driven by said power shaft,all as will hereinafter more fully appear.`

In the accompanying drawings:-

Fig. l, is a longitudinal sectionalelevation of the primary pinion ofthe gearing of a hoisting machine in associated relation to the powershaft and fixed bear-ing for an end of the shaft, and having theypresent improvement applied.`

Fig. 2, is a detail longitudinal section on line 2 2, Fig. ll, of one ofthe ratchet pawls', its operating cam studs and accessories.

Fig. 3, is a similar section on line 3 3, Fig. i, of the companionratchet pawl of the mechanism.

Fig. 1l, is a transverse sectional elevation on line Fig. 1, with thestationary parts of the mechanism omitted, and showing the ratchet pawlsheld in a retracted and inactive position and with the power shaft indirect operative engagement with the pinion for driving the same in thecontra-.clockwise direction indica-ted by an arrow on said figure.

Fig. 5, is a companion view toY Fig. 4, showing the position of theparts, with one of the ratchet pawls released when the pinion turns in aclockwise direction in advance of the power shaft through accidentalstoppage orfailure of the motive power connection of said shaft.

Fig. G, is a companion View to. Fig. 5,

showing the position of the parts with the other of the ratchet pawlsreleased, when the aforesaid pinion turns in a contraclockwise directionin advance ofthe power shaft, through the causes mentioned in connectionwith Fig. 5.

Fig. 7, is a companion view to Fig. 4:, showing the ratchet pawls in aretracted and inactive position when the power shaft is in directoperative engagement with the aforesaid pinion and moving said pinion ina clockwise direction as indicated by an arrow on the figure.

Fig. 8, is a detail sectional elevation of the ratchet disk, normallystationary with the lined frame or support of the mechanism.

Fig. 9,V is a detail perspective view of a ratchet pawl and itsoperating cam stud on the power shaft, the parts being shown inseparated relation. f

Like reference numerals indicate like parts inthe several views, 4,

In the present safety mechanism, the primary or driving pinion l of ahoistingr or like mechanism, is connected to the power shaft 2 uponwhich said pinion is carried, by a spline or key 3 having limitedindependent turningmovement in a keyway i of the elongated form` shown,so that limited independent turning movement between the pinion andpower shaft is provided for the purpose hereinafter set forth.

The end of the power shaft 2 carrying the pinion l, is journalled inatiixed bearing box 5 on the, frame orhousing of the mechanism, andassociated withsaid bearing boX 5, or like stationary part of the frame,is ratchet disk 6, the circiilarlyr arranged ratchet recesses 7 of whichare in adjacent relation to an end of the pinion 1 aforesaid.

The ratchet 'disk 6 may forma fixed part of the bearing box 5 or otherfixed part of the carrying`frame of the mechanism, in the preferredconstruction however, the

ratchet disk 6 is frictionally attached to said box or frame, so as tobe capable of independent movement under a sudden and forcible stress,and thus avoid breakage of parts which is liable to occur, when theratchet pawls hereinafter described have sudden engagement with saidratchet. disk under a heavy load carried by a hoisting or like machine.The frictional engagement of the ratchet disk 6 and'a fixed part of thesupporting frame, such as the rbearing box 5, is preferably attained bythe arrangement of a flat marginal portion 6 of the ratchet disk betweena complementary disk or head S, fixedly connected to the bearing box 5,and an annular ring 8, with said head 8 and ring S held in adjustablefrictional contact with the marginal portion 6 of the ratchet disk by aplurality of clamping bolts 9, and with the bearing faces of said headand said ring preferably provided with annular inserts 10 of any .usualmaterial 'used in the present art to afford constant friction duringextended use.

In the present structure., the circularly arranged series of holdingrecesses 7 in the ratchet. disk 6, are preferably in the forms oftruncated sectors, as shown. to afford stop abutment at the respectivesides of each re cess for the reversely arranged ratchet pawls now to bedescribed.

A pair of ratchet pawls 11 and 12, ai'e movably mounted in the primarypinion 1 aforesaid, and preferably in a slidable inanner in longitudinalrecesses in said pinion, in which they have movement in a directiontowards the ratchet disk 6 through springs 13 kas shown in Fig. 1. Theratchet pawls 11, 12, with their holding recesses are located atopposite sides of the axis of rotation of the pinion 1, with the forwardand beveled end of the pawl 11 adapted for stop engagement with theratchet disk 6 when the piliion is turning in one direction, while theforward and beveled end of the companion pawl 11 .is adapted for stopengagement with the ratchet disk 6 when the pinion 1 is turning in adirection opposite to that above referred to.

Then the pawls 11, 12 are of a cylindrical shape, as shown in Fig. 1,they will carry splines or keys 14 moving in keyways in the pinion 1 toprevent turning of the pawls from their proper position.

In the present improvement it is required that the pawlll or pawl 12which would normally act to hold the pinion 1 from rotation in thedesired direction, be held in a retracted and inactive position during anormal rotation of the pinion 1 and power shaft 2 in the desireddirection, and to s'uch end each pawl l1, 12 is formed with an inclinedor cam face 15, 15 facing in the same direct-ion as shown in Figs. 1, 2and 3, with said cam faces adapted to be alternately and operativelyengaged by cam studs or projections 16, 16 on opposite sides of thepower shaft 2, so that with a cam stud 16 in operative engagement withthe cam face 15 of a ratchet pawl 11 to hold the same in a retractedposition, the other cam stud 16 will be out of engagement with the camface 15 of the'pawl 12, to permit the same to move into stop enga-gementwith the ratchet disk 6, unless otherwise restrained as hereinafter Asetforth, and vice versa.

During the normal operation of the mechanism, in either direction it isrequired that the ratchet pawl which is not held in re straint byengagement of its cam face 15 or 15 and cam stud 16 or 16 be held in aretracted and inactive position with a view to avoid a noisy clicking inthe mechanism, and to such end a guard or holding member is provided, asfollows:

A circular guard disk 17 formed with a pair of opposed openings 18,preferably of a segmental form, is loosely mounted on the power shaft 2,and has frictional contact with the ratchet disk 6, preferably throughan annular ridge 19 near its outer rim engaging in a complementaryannular recess in the ratchet disk 6 and held to frictional engagementby spring impelled sliding heads 20 mounted in the primary pinion 1.Said guard disk 17 is operatively connected to the pinion 1 by a stud 21on the pinion, moving in an elongated curved slot 22 in the disk 17 toadmit of limited independent movement between the parts, preferablycorresponding in extent with that of the heretofore independent movementbetween the pinion 1 and power shaft 2. Such provision for independentmovement of the guard disk 17 may be between the guard disk and thepower shaft 2, when found most convenient.

The operation of the mechanism is as fol- 'lows:-

Vith the parts in the position shown in Fig. 4, the power shaft 2 ismoving in the contra-clockwise direction indicated by the arrow in saidfigure and driving the pinion l in the same direction. In such normaldriving condition, the cam stud 16 is in engagement with the cam face 15to hold the ratchet pawl 11 in a retracted position as shown in Fig. 2,while the companion cani stud 16 is out of engagement with the cam face15 of its ratchet pawl 12, but with said ratchet pawl 12 held in aretracted and inactive position by the engagement of an edge of theopening 18 of the guard plate 17 beneath the point of the pawl 12 asshown in Fig. 3.

`With a stoppage of the power shaft 2, through loss of power, due to aneutral position of the reversing mechanism of the hoisting apparatus,etc., and with the load carried. tending to turn the pinion 1 in a Lilclockwise direction as indicated by the arrow on Fig. 5, the action isas follows The pinion 1 moving in a clockwise direction under the load,and in a manner independent of the guard disk 17, by travel of its stud21 in the elongated slot 22 of said disk, carries the ratchet pawl 12from under the guard disk 17, to a released condition and so that saidpawl will move into locking engagement with the ratchet disk 6 to stopand hold the pinion 1 against further turning movement and thus preventa runaway of the hoisting mechanism. under the stress of the abovementioned load.

lith the load carried tending to turn the pinion 1 in acontraweloclnvise direction as indicated by the arrow in Fig. 6, theaction is as follows:

The pinion 1 turning in such contra-clock wise direction, moves by meansof its keyway 4, independent of the power shaft 2 and its spline 3, tocarry the ratchet pawl 11 out of engagement with the cam stud 16, and jiermitting said pawl 11 to move into lock ing engagement with theratchet disk 6 to stop and hold the pinion 1 against further movement inthe described contra-clockwise direction. ln such operation the. stud 21of the pinion 1 has initial independent move ment in the elongated slot22 of the guard disk 17 but in a final movement engages and moves theguard disk to the position indicated in Fig. 6, for a succeedingstep inthe operation of the mechanism.

lith the parts in the position indicated in Fig. 7, the power shaft 2 ismoving in the clockwise direction indicated by the arrow on said figure,and driving the pinion 1 in the same direc-tion. In such normal drivingcondition of the parts, the cam stud 16 is in engagement with the camface 1.5 to hold the ratchet pawl 12 in a retracted and inactiveposition, while the companion cam stud 1G is out of engagement with thecam face 15 of the ratchet pawl 11, but with said pawl held in aretracted and inactive position by the engagement of the opening 18 ofthe guard disk 17 beneath the point of the pawl 11. With the describedposition of the parts, the normal driving of the pinion 1 by the powershaft 12 continues until such accidental occurrences as above set forthin the contra-clockwise driving of the pinion 1 takes place when thesafety operation of the parts takes in substantially the same way but ina reversed manner.

Having thus fully described my invention, what I claim and desire tosecure by Let-ters Patent is t 1. In a safety mechanism of the typedescribed, the combination of a fixed support, a power shaft journalledin said support, a driven member mounted on said shaft, means forpermitting limited independent turning movement between said shaft anddriven member, a ratchet disk carried by the fixed support, reverselyarranged pawls carried by the driven member for stop engagement withsaid ratchet disk, cam projections on the power shaft having alternatingengagement with said pawls to retract the same, and an orificed guarddisk associated with the power shaft and driven member for alternatingretracting engagement with said pawls.

2. In a safety mechanism of the type described, the combination of afixed support, a power shaft journalled in said support, a driven membermounted on said shaft, means for permitting limited independent turningmovement between said shaft and driven member, a ratchet diskfrictionally held on said fixed support, reversely arranged pawlscarried by the driven member for stop engagement with said ratchet disk,cam projections on the power shaft having alternating engagement withsaid pawls to retract the same, and an orificed guard disk associatedwith the power shaft and driven member for alternating retracting engagement with said pawls.

3. In a safety mechanism of the type described, the combination of afixed support, a power shaft journalled in said support, a driven membermounted on said shaft, means for permitting limited independent turningmovement between said shaft and driven member, a ratchet diskfrictionally attached to the fixed support by a circular head fixed onsaid support, a companion ring attached to said head by clamping bolts,and a fiat marginal extension on the ratchet disk arranged between saidhead and ring, reversely arranged pawls carried by the driven member forstop engagement with said ratchet disk, cam projections on the powershaft having alternating engagement with said pawls to retract the.same, and an oriticed guard disk associated with the power shaft anddriven member for alternatine retracting engagement with said pawls.

la In a safety mechanism of the type described, the combination of afixed support, a power shaft journalled in said support, a driven membermounted on said shaft, means for permitting limited independent turningmovement between said shaft and driven member, a ratchet disk carried bythe fixed support, reversely arranged pawls slidingly mounted in saiddriven member at opposite sides of its axis of rotation, springs formoving said pawls in one direction, cam projections on the power shafthaving alternating engagement with said pawls to retract the same, anorificed guard disk associated with the power shaft and driven memberfor alternating retracting ei'igagement with said pawls.

In a safety mechanism of the type described, the combination of a ixedsupport, a power shaft journalled in said support, a driven membermounted on said shaft, means for permitting limited independent turningmovement between said shaft and driven member, a ratchet diskrictionally held on said fixed support, reversely arranged pawlsslidingly mounted in said driven member at opposite sides of its axis ofrotation, springs for moving said paWls in one direction, camprojections on the power shaft having alternating enga-gement with saidpawls to retract the same, and an oriliced guard disk associated withthe power shaft and driven member Yfor alternating retiactingengagenient with said pawls.

o'. In a safety mechanism of the type described, the combination ot' aiixed support, a power shaft joui-nailed in said support, a drivenmember mounted on said shaft,

means for permitting limited independent turning movement between saidshaft and driven member, a ratchetdisk frictionally attached to thefixed support by a circular head lixed on said support, a Companion rinattached to said head by clamping bolts anc a flat marginal extension onthe ratchet disk arranged between said head and ring, reversely arrangedpawls slidingly mounted in said driven member at opposite sides of theaxis of rotation thereof, springs for moving said pawls in onedirection, cam projections on the power shaft having alternatingengagement with said pawls to retract the same, and an oriliced guarddisk associated with the power shaft and driven member for alternatelyret acting engagement with said pawls.

Signed at Chicago, illinois this 11th day of April, 1925.

EDWTARD J. POW/VERS.

